Why is when I diactivate the object grid horse shoe on the browser when I zoom into an object at 1%, the object jumps not slides like it does at lower resolution
Video is a sequence of frames (images), at this zoom level you are seeing the timeline at the frame level so any movement is by a whole number of frames.
Depending on the framerate this would be for example 1/25 th of a sec for 25 fps video.
I'd say simply because video is 'frame' based. You can't have something positioned between the frame boundaries which are say one twenty-fifth of a second apart.
Note the timeline divisions are hr:min:sec:frames, and when zoomed this far they show real values, not the more usual constant '00'.
You are zooming down and seeing the individual frames. The smallest unit is 1 frame and all objects snap to the head or tail of a frame. The first unit or frame starts at the beginning and the timeline is divided into frames.
The Object grid is there so that objects snap to the head or tail of another object, leaving no gap. Imagine trying to butt one object against another without zooming in to frame level. Unless you have good reason to, I suggest that you leave it on or you may find that you have blank frames on your timeline, which is undesirable.